Hey anh, I didn't know you were here too. Have you compared it to the moded AE?

Hey Quan! I don't think PCM2705 is potential for modification so I didn't spend much time with AE. I think the moded AE lack detail. Will try take USB signal from AE and send it to TE7022. It makes this DAC become more convenient with wireless

@diykast: I would take some pics, perhaps in this weeken when have time to finish. Now this work with bread board like a mess

I didn't know the current draw for both the usb isolation board and the dac so I just use one relatively large heat sink that I have on hand. In fact, I can't feel any heat when I touch it. It seems very low current is drawn by the circuit.

I chose 9vac because the isolation board specification requires min 8vdc. 9vac gives 10vdc after retification and filtering. Note that the Isolation board has its own discret regulator. I think max drop out on lt1963 is 2v and max drop out on the onboard discret regulator is 3v.

In fact there are 3 regulator before the DAC chip. Lt1963 - onboard regulator of the isolation board and then LT1763 on the DAC pcb. Therefore i think ripple rejection would be good.

May be inserting a current regulator in place of lt1963 is best but lt1963 and the pcb is readily available to me... Do you have any recommendation on this? Which other chip is better?

For v2 with integrated isolation chip you may use lower ac voltage. I personnally also prefer supply voltage as low as possible. Not just less heat but also better sound to my ears. More current reserve is better but too high voltage is not good.